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I have a power meter model PM 750 and PLC model no TWDLC-E40DRF . I need to obtain address 4001 on my PLC through its modbus rtu port .

Power Meters or Power Monitors PM500,700& PM800 series can communicate with twido on Modbus.
Twido understands %M ( Memory bits) & %MW( Memory words) for Modbus protocol communication, so, whatever Power meter  you use, you have to have to map the Modbus address of that particular Power meter in %MW of Twido.

we are considering Power Meter PM750.

1) Power Meter P750 supports ModbusRS485 -2wire.
With Twido, the address is not important to differentiate a master or a slave, If Twido is a master, you use the EXCH instruction with tables.

In Twido you have 3000 %MW max & PM750 you have many Register (4000, 7000, etc ...) .
Twido controller can communicate with Power Meter PM750 on Modbus using EXCH instruction
Communication of Twido as Master & PM750 as Slave on Modbus using EXCH instruction is similar to Twido Master to Twido Salve on Modbus.
Please refer to attached file for Modbus application using EXCH instruction and sample Code to read CT Ratio – Primary ( Modbus address 4120 ). Also, we have included PM750 instruction bulletin in file (Refer to page 37)
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